29GHz-Bandwidth Monolithically Integrated EAM-VCSEL

The increase in modulation bandwidth of a vertical-cavity surface-emitting laser (VCSEL) can be achieved through the vertical integration of a modulator onto the laser. This approach has already been proposed and demonstrated to be competitive [1-3]. In this specific case, a double mesa structure with three contacts is needed to apply a high-frequency voltage signal to the modulator section and inject a CW current into the underlying VCSEL section. The middle contact serves as a shared ground. Indeed, splitting the emitting and the modulating parts circumvents the carrier dynamics limitation of the modulation bandwidth encountered in direct current-modulated VCSELs. However, the parasitic capacitances of the access line and contact pad play a significant role in the high-frequency limit of such a device.